Connectors for railcars are usually pivotally attached to each end of a car center sill. A convex end of a male connector part normally rests against a follower block held within a female sill pocket casting that is mounted within the car sill to withstand longitudinal forces tending to thrust the connector into the sill (compressive or buff loading). The connector is held from being withdrawn from the sill by pulling forces (draft loading) by a pin or drawbar or by a collar that is spaced from the follower block. Several types of connectors are available to extend between successive railcars such as couplers, drawbars and articulated connectors wherein there is a single pivotal connection between male and female members that are rigidly attached to the adjacent ends of successive car platforms.
In newly assembled connectors the clearances between the aforementioned parts are minimal and there is virtually no slack or movement of the parts longitudinal of the car when forces on the connectors are reversed, as occurs each time the car is accelerated or decelerated. However, usage induces wear on various parts and gradually spaces will be created. Such spaces are known as slack. Slack is undesirable as it causes repetition and magnification of impact forces when a train of cars is accelerated and decelerated. Yet a degree of slack in each pivotable connection is needed for the purposes of assembling and disassembling the parts, which must be done from time to time.
Ordinarily in freight car construction slack is compensated and taken up by locating a wedge shaped shim between two of the connector parts, usually between the follower block and a closed end of a sill pocket as shown in prior U.S. Pat. Nos. 3,716,146, 4,456,133 and 4,549,666. As will be seen in the prior art, the wedge usually inserts downwardly by gravity although it can be spring loaded in other directions. In articulated connectors a wedge is placed between the follower block and an end wall of the female member as shown in prior U.S. Pat. Nos. 4,258,628, 4,336,758 and 4,593,829. In operation the wedge becomes further inserted to maintain compression between the parts as wear enlarges the spaces.
The wedge must be replaced or the connector otherwise serviced when the wedge becomes fully inserted. Ordinarily a viewable wear indicator is provided on the wedge side. The most common indicator has been a groove cut on a tab extending from each side of the wedge; and portals or holes are located in the sill or articulated connector near the bottom of the female pocket.
When it becomes necessary to disassemble such connections the wedge must be partially withdrawn so as to release compression and permit the parts to be removed. Heretofore it has been necessary for mechanics to insert a tool, such as a prybar, against the bottom or a side tab of the wedge and lever it outward. The wear indicator portals in the sides of some structures have been utilized to provide access for such tools; and the aforementioned tabs at each wedge side have been contact points for such inserted tools. An example of such construction for articulated connectors is illustrated in U.S. Pat. No. 4,593,829.
However, it will be understood that the location of such tabs has been primarily chosen to indicate a fully inserted (worn) position of the wedge with the result that it has been very difficult to position a tool for adequate leverage against the tabs when the wedge is nearing but has not reached a fully inserted position.
In some connector constructions this is not a formidable problem as a broad access opening may be available from directly beneath a gravity wedge, and it is a simple matter to insert a tool directly against the wedge bottom and force it upward. Indeed it has been proposed to include an extension piece on some wedge designs to act as a wear indicator and also to enable the wedge to be withdrawn without a separate tool. An example of such a wedge and extension is shown in U.S. Pat. No. 4,946,052. However, these features are not compatible with all connector arrangements particularly where access holes or view ports at the sides must be relied on for access. For example for strength reasons the articulated connectors illustrated in the aforelisted patents are not suitable for bottom openings but do contain side inspection portals.